Bovine serum albumin binding property of Dy(III) and Tm(III) complexes based on pyridine-2-carboxylic acid

Two isomorphous mononuclear complexes [M(tpc)(3)(H2O)(3)]center dot H2O, where M=Dy (1), Tm (2), were synthe-sized through the reaction of 5-(trifluoromethyl) pyridine-2-carboxylic acid (Htpc), DyCl3 center dot 6H(2)O, and TmCl3 center dot 3H(2)O. The crystallographic details of complexes 1 and 2 reveal a monoclinic crystal system with the P2(1)/c space group. Metal ions in the two complexes are eight-coordinated and located in the slightly deformed dodecahedron geometry. The fluorescence data reveal that complexes 1 and 2 could interact with bovine serum albumin (BSA) through the static quenching mechanism with the quenching constant K-sv ranging from 10(5) to 10(6) L center dot mol(-1). Hydrophobic interaction plays an important role in the interaction of complexes and BSA since both Delta H and Delta S values are positive. The binding constant between the two complexes and BSA was about 10(4) L center dot mol(-1) at 25 degrees C, which indicates the complexes and BSA have moderate interactions. CCDC: 2208380, 1; 2208382, 2.